Cardiotoxicity secondary to Adriamycin is a serious problem. The mechanisms generally attributed to its toxicity involve free radial mediated injury. One of the important consequences of excessive free radical generation in the cardiovascular system is the depletion of Nitric Oxide (NO). NO is a key signaling molecule that is required in diverse cellular processes and is also involved in the preservation of systolic and diastolic function. Modalities that either deplete or enhance cardiac NO are known to influence myocardial function negatively or positively respectively. Vessel wall endothelial function may be used as a non-invasive read-out of systemic NO availability. In this study we propose to use this simple modality to evaluate the effects of acute Adriamycin administration used in current chemotherapeutic protocols. We will also simultaneously obtain data on diastolic function of the heart using a novel method-3D echocardiography to provide a correlate of myocardial function.